import React, {Component} from 'react'
import PropTypes from 'prop-types'
import {nanoid} from 'nanoid'
import './index.css'

export default class Header extends Component {

  // 对接收的props进行：类型、必要性的限制
  static propTypes = {
    addTodo: PropTypes.func.isRequired
  }

  // 键盘事件的回调
  handleKeyUp = (event) => {
    // 解构赋值获取keyCode,target
    const {keyCode, target} = event
    // 判断是否是回车按键
    if (keyCode === 13) {
      // 添加的todo名字不能为空
      if (target.value.trim() === '') {
        alert('输入不能为空')
        return
      }
      // 准备好一个todo对象
      const todoObj = {id: nanoid(), name: target.value, done: false}
      // 将todoObj传递给App
      this.props.addTodo(todoObj)
      // 清空输入
      target.value = ''
    }
  }

  render() {
    return (
      <div className="todo-header">
        <input type="text" onKeyUp={this.handleKeyUp} placeholder="请输入你的任务名称，按回车键确认"/>
      </div>
    )
  }
}
